1. Field of the Invention
The present invention relates to document facsimile, or pictorial storage on a recording medium, and more particularly to a document information storage system providing either video display or hard copy reproduction of stored document information.
2. Description Relative to the Prior Art
It is known in the art to record video program material on a disc-shaped recording medium. Typically, the video program material is comprised of a series of sequential frames. Each frame comprises two sequential interlaced fields, i.e., an odd field containing the odd lines of video information (lines 1, 3, 5, . . .), and an even field containing the even lines of video information (lines 2, 4, 6, . . .). The information is commonly recorded in a circular or spiral record track configuration, with one frame, or one field, recorded per disc revolution.
The video disc represents a potentially valuable medium for document information storage applications. The information of each document (i.e., each page) can be recorded as a single frame of information. It is feasible, with present video disc technology, to store tens of thousands of document "frames" on a single side of a 300 mm (12 inch) diameter disc. Further, because of the manner in which discs are read, a random access system is possible wherein any one of the document frames stored on the disc could be located and displayed in seconds. There are certain problems peculiar to document frame storage, however, which inhibit the straightforward application of video discs to such storage.
In business system applications, i.e., where frames corresponding to documents such as bank checks and the like are to be stored, it is important to have both high storage capacity (many document frames stored per disc) and a useful storage format (one document frame stored per disc rotation so that individual still frame aquisition and video display of the stored document frames can be accomplished). A document frame storage system for business system applications should preferably provide the option of hard copy reproduction in addition to video display of the stored document frames. These two playback modes are somewhat incompatible because conventional video monitors require sequential field information (the odd field information and then the even field information), whereas many conventional printer devices require sequential line information (line 1 from the odd field, line 2 from the even field, line 3 from the odd field, and so on).